AlGaN-based high-performance metal–semiconductor–metal photodetectors

✍ Scribed by Mutlu Gökkavas; Serkan Butun; Turgut Tut; Necmi Biyikli; Ekmel Ozbay

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 909 KB
• Volume: 5
• Category: Article
• ISSN: 1569-4410
• DOI: 10.1016/j.photonics.2007.06.002

✦ Synopsis

Design, structure growth, fabrication, and characterization of high performance AlGaN-based metal-semiconductor-metal (MSM) photodetectors (PD) are reported. By incorporating AlN nucleation and buffer layers, the leakage current density of GaN MSM PD was reduced to 1.96 Â 10 À10 A/cm 2 at a 50 V bias, which is four orders of magnitude lower compared to control devices. A 229 nm cut-off wavelength, a peak responsivity of 0.53 A/W at 222 nm, and seven orders of magnitude visible rejection was obtained from Al 0.75 Ga 0.25 N MSM PD. Two-color monolithic AlGaN MSM PD with excellent dark current characteristics were demonstrated, where both detectors reject the other detector spectral band with more than three orders of magnitude. High-speed measurements of Al 0.38 Ga 0.62 N MSM PD resulted in fast responses with greater than gigahertz bandwidths, where the fastest devices had a 3-dB bandwidth of 5.4 GHz.